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C-40 Preamp

tuffstuff1

Super Member
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I am looking at one of these and would like to know what makes it better (or worse) than my C-28 or C-26. Thanks a lot. Reposted beacuse I accidenatally put MC-40 in the title. Duh.
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I am looking at one of these and would like to know what makes it better (or worse) than my C-28 or C-26. Thanks a lot. Reposted beacuse I accidenatally put MC-40 in the title. Duh.
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Well, where do we start.....??

Reliability for a start with the C40......

The performance is lightyears ahead of the C26-28 period. SNR and THD is as good as the latest line of Mc pre-amps...

5 band EQ

It features solid state logic switching for inputs and outputs using a logic circuit which operates these sealed rhodium relays, they are vacuum sealed and rhodium contacts never corrode giving a lifetime of reliable switching....

Compandor

Monitor amplifier featuring powerguard

Variable loudness

New Generation McIntosh sound......(which I prefer)

Its a powerful package and I love mine, as soon as I plugged it in and the first note came out of it, I was "thats it!!, Thats the sound I want!!"

They do fall between the cracks because they don't have a remote, and that does bother me a little bit, but not that much.....

I am definitely keeping mine despite the fact I will be getting either a C48 or C2500 later in the year......

You simply can't go wrong with the C40, its a great pre-amp....

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That's what I hoped. I like all those factors. My controls are getting a little scratchy. I worry about the volume pots. I do not know what new generation sound is. What sonic differences might I expect? I don't like the stepped volume on the C28. I like the look of the C28, 26 because it matches the M74 tuner. That's not such a big deal to me. I read about the downside of the phono section of the early MC pre. Is there a big difference in the phono between the early and C40? The main reason I am asking is because I am building a brand new Thorens TT. I found a brand spak'in new TD125 and just bought a new Sure M2-9 and a ortofon black cart. I don't want to defeat the purpose of the great TT/cart with a sub-par pre phono section. If it won't be that noticable to my ears then I will just stick with the C28 or maybe back to the C26 because the C26 loudness is not stepped. Thanks a lot
 
That's what I hoped. I like all those factors. My controls are getting a little scratchy. I worry about the volume pots. I do not know what new generation sound is. What sonic differences might I expect? I don't like the stepped volume on the C28. I like the look of the C28, 26 because it matches the M74 tuner. That's not such a big deal to me. I read about the downside of the phono section of the early MC pre. Is there a big difference in the phono between the early and C40? The main reason I am asking is because I am building a brand new Thorens TT. I found a brand spak'in new TD125 and just bought a new Sure M2-9 and a ortofon black cart. I don't want to defeat the purpose of the great TT/cart with a sub-par pre phono section. If it won't be that noticable to my ears then I will just stick with the C28 or maybe back to the C26 because the C26 loudness is not stepped. Thanks a lot

The New Mc sound to me is crystal clear and defined with incredible detail, but retaining that certain warmth with a full bass (not bloated)......

The volume control is also stepped on the C40, but if you get you gain structure right with your power-amp, it wont cause you any issues....

The phono pre on the the C40 is way superior to what they were using back in the C28 days, less distortion, more dynamic range....
I run a TD125MK2/SME3009 with a Shure M97XE which has a JICO SAS stylus.....before I got the C40 I was thinking of getting a better turntable.....well, once the C40 was in place, I soon forgot about that, I think the C40 phono pre is pretty damn good.

I noticed quite a substantial difference moving from the C32 to the C40.....

The C40 is the first of the series where the width changed, they are wider than the C32, 28, 26 era of Mc's.

I dont think you'll be disappointed with the C40, it really is the last of the classic style before they went with digital displays and encoders rather than real controls.....

You can see the width difference here with my MR78 sitting on top of the C40....sorry about the crap picture....but you get the idea...
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Beautiful setup Kev. I think I am going to go after this. They must be pretty rare because I can't find much opinion on it. There has not been any sold on the bay. It must have been a low production model, either that or nobody wants to part with theirs.
 
It also sounds great without a amp it has a 40 watt per channel monitor amp that kicks on it's own
 
A C-28 doesn't have a stepped volume control, in fact it had one of the worst tracking volume controls of any Mac pre-amp. If you have a stepped control its not original and some has been tinkering with the pre-amp. The C-40 is the last of the full functioning pre-amps Mac made with the full Mode selector, record selector and listen selector. It has the processor loops and the built in power amps that work great with electro static headphones or efficient rear ambient speakers if your so inclined. The C-28 has an overly warm sound on the phono inputs as it uses discrete components and unless your unit has been upgraded suffered from crosstalk between channels on the phono inputs. The steps are so close together on the pre-amps built after the early 90's you really can't discern the steps unless you have a gain mismatch between the pre-amp and power amp. Are you operating your amps with the controls set at the 12:00 o'clock position ? (2.5 volts). My C-29 that replaced the 28 was a significant step up. The C-34 another step up and because of space in my hifi cabinet I can't install a C-40 or I would! They sound great. The newer pre amps have one feature the older pre-amps don't. Variable gain for each input so you can match input sources with fixed output levels for similar over all output level of the pre-amp.
 
I said loudness and meant to say stepped bass. Sorry to confuse. Great to know that there is a 40 watt amp built in. I don't know that I would ever use it, but it's a cool feature. I keep the gain at about 1:00. It seems I can get away with 1:00 and not get significant hiss. That is another thing that is a little annoying, the hiss. I would imagine the hiss is coming from the amps though, not the pre, so the C-40 would not do anything to subside the hiss? When the gains are all the way up and I adjust the volume on the pre the hiss is worse than 1:00 gains pre up. It is also hard to get the gains exact matching on the twin MC250 without meters. I think that is where I may be getting the "crosstalk", as you speak. I am not sure if the C-28 had been upgraded or not. Is there a way to tell? It sure is a pretty unit. Is is perfect appearence wise in every way. I almost feel it may be worth it to sell off both the C-28 and C-26 and get the C-40. I can probably still be ahead of the game $$$$ wise and I don't need both anyway. Improved performance all the way around. What do you think? Thank you for your replies.
 
I said loudness and meant to say stepped bass. Sorry to confuse. Great to know that there is a 40 watt amp built in. I don't know that I would ever use it, but it's a cool feature. I keep the gain at about 1:00. It seems I can get away with 1:00 and not get significant hiss. That is another thing that is a little annoying, the hiss. I would imagine the hiss is coming from the amps though, not the pre, so the C-40 would not do anything to subside the hiss? When the gains are all the way up and I adjust the volume on the pre the hiss is worse than 1:00 gains pre up. It is also hard to get the gains exact matching on the twin MC250 without meters. I think that is where I may be getting the "crosstalk", as you speak. I am not sure if the C-28 had been upgraded or not. Is there a way to tell? It sure is a pretty unit. Is is perfect appearence wise in every way. I almost feel it may be worth it to sell off both the C-28 and C-26 and get the C-40. I can probably still be ahead of the game $$$$ wise and I don't need both anyway. Improved performance all the way around. What do you think? Thank you for your replies.
Ron-C made a comment long time ago (paraphrasing) that the reason not many C40's exist is that the rest of the world had moved on to wireless remote but the C40 did not have it.
 
Nobody appreciates vintage McIntosh more than I but I have to agree with Kev and give the nod to the C 40 - if within your budget and you're able to find one.

Specs & reliability are both significantly improved and the off/on volume control is often cited as a perennial headache on C 26/28.

I don't think you could go wrong with a C 40, C 29, 30, 33, 34.
 
Ron-C made a comment long time ago (paraphrasing) that the reason not many C40's exist is that the rest of the world had moved on to wireless remote but the C40 did not have it.

The c30 was like that......the c40 was the last full featured preamp w/o a remote. There were other Mac preamps with remote while the c40 was current.

The c28, and some what the c26, make great project preamps. The s/n, volume control tracking, etc. etc can all be improved, but it still will not be a c40, or a c33, etc.
 
When I used 2105's and 2505 with Klipsch speakers, we found the C-26 to noisy with the volume controls on the amps set at 12:oclock and went back to using c-22 while they were still available. And I totally agree with you about the tone controls steps being to large. I really enjoy the tone controls on my C-34 for that reason and My MX-120. Having the 1 db change on the 120 is wonderful. The big thing I miss is being able to adjust the left and right separately from each other. On some classical recordings I always feel the treble needs to be kicked up a notch or two to get the right presentation of the Cellos and double basses. Just adding more signal with the balance control is not the solution. Everytime I would see Davie Obrien after the C-32 came out I asked when Mac was going to use coaxial controls for the graphic EQ's.
 
Is the C-41 exactly the same pre as the C-40, but only the difference is it utilizes a remote?

The model number might suggest it was an upgrade from the C40 but no. Although the C41 was several years newer, it had nowhere near the features of the C40 and was a fairly basic pre, plus it was around a grand cheaper.
There weren't many C41 made so it's also quite rare, but it might well sound as good as a C40; only someone who has compared them would know.

I haven't heard a C40 but it was Mac's TOTL single chassis pre of that generation. If you can find one and you can live without the remote, I'm quite sure it sounds fantastic and possibly as good as the current single chassis pres.
I have the C712 which was the the entry level of the same generation as the C40, and the 712 sounds sounds wonderful to me, so the C40 would have to sound at least as good and likely better.

A curious thing about those mid 90's pres that hopefully someone could explain; according to the specs, they have the highest S/N of any Mac pres I've seen, and yet Ron-C says the newer ones are quieter. How can this be?
As for the C40 being the only pre of that generation without remote, I suspect it may be because it had a true stepped volume attenuator which is more complex and quite large, so maybe it wasn't feasible or practical to attach a motor; but perhaps someone here more knowledgeable could answer that.
 
As Mortis said, C 41 is more basic - 5 band EQ, C var loudness, compander are the more obvious features lacking - probably the monitor internal amplifier as well.

Kind of a shame Mc never offered remote on the all-glass fronted pres, C 29 - C 34. That series is my favorite, aesthetically.
 
Kind of a shame Mc never offered remote on the all-glass fronted pres, C 29 - C 34. That series is my favorite, aesthetically.

You do realize that back then we had to get up every 20 minutes or so and change the LP......

Trying to remember what we might have had on the sales floor in 1983 (when the above units were current) that had a remote.

B&O 6000,8000,5000 had that market covered

Mitsubishi DP101 cd, tandberg decks via outboard sensor, Revox decks????

I think the remote capable replacement for the c40 was the c42 if memory serves me right.
 
The model number might suggest it was an upgrade from the C40 but no. Although the C41 was several years newer, it had nowhere near the features of the C40 and was a fairly basic pre, plus it was around a grand cheaper.
There weren't many C41 made so it's also quite rare, but it might well sound as good as a C40; only someone who has compared them would know.

I haven't heard a C40 but it was Mac's TOTL single chassis pre of that generation. If you can find one and you can live without the remote, I'm quite sure it sounds fantastic and possibly as good as the current single chassis pres.
I have the C712 which was the the entry level of the same generation as the C40, and the 712 sounds sounds wonderful to me, so the C40 would have to sound at least as good and likely better.

A curious thing about those mid 90's pres that hopefully someone could explain; according to the specs, they have the highest S/N of any Mac pres I've seen, and yet Ron-C says the newer ones are quieter. How can this be?
As for the C40 being the only pre of that generation without remote, I suspect it may be because it had a true stepped volume attenuator which is more complex and quite large, so maybe it wasn't feasible or practical to attach a motor; but perhaps someone here more knowledgeable could answer that.

The sound of the C40 is VERY impressive......now I can only compare it to my refurbed and recapped C32 which it completely blows out of the water.......


I noted its specs too......I tell people it has the same SNR and THD as the new models, its so close you'd never be able to tell the difference.....My black background of my system became a whole lot 'blacker' (is that a word?') when the C40 was put in the system....

The audio controls on the remote models are in fact just digital encoders (they are usually optical) rather than motors on regular analouge controls....
This allows then to keep all the analogue path right at the back of the unit by all the connectors and have no audio routing past power supplies and picking RFI etc etc......

I think the remote capable replacement for the c40 was the c42 if memory serves me right.

This is correct as I discovered in my research when I was buying a pre-amp.......
I stayed away from the C42 as it was the first attempt at digitizing the audio controls for Mc, and they didn't quite get it right, for the volume, rather than it reacting as though it were a analogue control with about 300˚ on rotation for a full sweep, you would have to wind and wind and wind doing multiple turns with the encoder.
Apparently the EQ controls were the same....
That to me is bad control ballistics, some of the early digital mixing consoles were like this too, makes it difficult to control things when they behave like that....
By by the C46 they got it right though, and I am looking forward to getting a C48 or C2500 some time later in the year.....
 
The audio controls on the remote models are in fact just digital encoders (they are usually optical) rather than motors on regular analouge controls...

As far as I can tell, the audio controls on the mid 90's pres are as you say digitized, except the volume pot which had a motor attached and the knob turns as you change volume. At least that's the way it is on the 712. Here's a pic of my 712 V pot:

i-7nB7H7r-L.jpg
 
As far as I can tell, the audio controls on the mid 90's pres are as you say digitized, except the volume pot which had a motor attached and the knob turns as you change volume. At least that's the way it is on the 712. Here's a pic of my 712 V pot:

Oh yes right, this was one way of doing it, and I was unaware that this was the way Mc have worked it on some models.....
I was more talking about the evolution of the C40,42,46.....the full featured TOTL 2ch pre's........I could have made that clearer, as those are ones I know about.....
The C42 was a digital encoder.....

Your one there is still analogue with the actual analogue signal passing through as opposed to the digital encoders which do not have any audio passing through them....

Is the volume on yours a stepped volume control?
 
Oh yes right, this was one way of doing it, and I was unaware that this was the way Mc have worked it on some models.....
I was more talking about the evolution of the C40,42,46.....the full featured TOTL 2ch pre's........I could have made that clearer, as those are ones I know about.....
The C42 was a digital encoder.....

Your one there is still analogue with the actual analogue signal passing through as opposed to the digital encoders which do not have any audio passing through them....

Is the volume on yours a stepped volume control?

No its not stepped, but as expected, it appears to be very high quality. Am I correct in saying your C40 IS stepped? Have you had a look inside the case, and if so, is the pot a fairly large module?

BTW, I don't think Mac has ever made any of their multi-band EQ's digitized. I believe they are still all analogue right up to the latest models.
 
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